/* Color Palette and System Variables (Light Mode Default) */
:root {
    --primary: #0a192f;
    --primary-light: #1e293b;
    --accent: #0288d1;
    --accent-glow: #38bdf8;
    --text-main: #334155;
    --text-muted: #64748b;
    --bg-light: #f8fafc;
    --white: #ffffff;
    --card-bg: #ffffff;
    --border-color: #e2e8f0;
    --img-slot-bg: #f1f5f9;
    --pre-bg: #0a192f;
    --contact-bg: linear-gradient(135deg, #e0f2fe 0%, #e1f5fe 100%);
    --radius: 12px;
    --shadow: 0 10px 30px -10px rgba(0, 0, 0, 0.08);
}

/* Dark Theme Overrides */
[data-theme="dark"] {
    --primary: #38bdf8;
    --primary-light: #1e293b;
    --accent: #38bdf8;
    --accent-glow: #7dd3fc;
    --text-main: #f8fafc;
    --text-muted: #94a3b8;
    --bg-light: #0f172a;
    --white: #1e293b;
    --card-bg: #1e293b;
    --border-color: #334155;
    --img-slot-bg: #0f172a;
    --pre-bg: #030712;
    --contact-bg: linear-gradient(135deg, #1e293b 0%, #0f172a 100%);
    --shadow: 0 10px 30px -10px rgba(0, 0, 0, 0.5);
}

* {
    box-sizing: border-box;
    margin: 0;
    padding: 0;
}

body {
    font-family: 'Segoe UI', -apple-system, BlinkMacSystemFont, Roboto, sans-serif;
    line-height: 1.75;
    color: var(--text-main);
    background-color: var(--bg-light);
    padding: 40px 20px;
    transition: background-color 0.3s ease, color 0.3s ease;
}

.container {
    max-width: 1050px;
    margin: 0 auto;
}

/* Back Button & Top Navigation Container */
.top-nav {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 24px;
}

.back-btn {
    display: inline-flex;
    align-items: center;
    gap: 8px;
    background-color: var(--card-bg);
    color: var(--accent);
    padding: 10px 22px;
    text-decoration: none;
    border-radius: var(--radius);
    font-weight: 600;
    font-size: 0.95rem;
    border: 1px solid var(--border-color);
    box-shadow: 0 2px 4px rgba(0,0,0,0.02);
    transition: all 0.2s ease;
}

.back-btn:hover {
    background-color: var(--accent);
    color: #ffffff;
    transform: translateY(-2px);
    box-shadow: 0 4px 12px rgba(2, 136, 209, 0.2);
}

/* Theme Switcher Toggle Button */
.theme-toggle-btn {
    display: inline-flex;
    align-items: center;
    gap: 8px;
    background-color: var(--card-bg);
    color: var(--text-main);
    padding: 9px 18px;
    border-radius: 20px;
    font-weight: 600;
    font-size: 0.9rem;
    border: 1px solid var(--border-color);
    cursor: pointer;
    box-shadow: 0 2px 4px rgba(0,0,0,0.02);
    transition: all 0.2s ease;
}

.theme-toggle-btn:hover {
    border-color: var(--accent);
    color: var(--accent);
}

.page-card {
    background: var(--card-bg);
    padding: 50px;
    border-radius: 16px;
    border: 1px solid var(--border-color);
    box-shadow: var(--shadow);
}

header.hero {
    text-align: center;
    margin-bottom: 40px;
    padding-bottom: 30px;
    border-bottom: 1px solid var(--border-color);
}

h1 {
    color: var(--primary);
    font-size: 2.3rem;
    letter-spacing: -0.5px;
    margin-bottom: 10px;
}

.subtitle {
    color: var(--accent);
    font-weight: 600;
    font-size: 1.05rem;
    text-transform: uppercase;
    letter-spacing: 1px;
}

.text-muted {
    color: var(--text-muted) !important;
}

h2 {
    color: var(--primary);
    font-size: 1.6rem;
    margin: 35px 0 15px;
    display: flex;
    align-items: center;
    gap: 10px;
}

p, li {
    margin-bottom: 18px;
    color: var(--text-main);
    font-size: 1.02rem;
}

/* Image Layout Components */
.img-slot {
    background: var(--img-slot-bg);
    border-radius: var(--radius);
    overflow: hidden;
    border: 1px solid var(--border-color);
    display: flex;
    align-items: center;
    justify-content: center;
}

.img-slot img {
    width: 100%;
    height: 100%;
    object-fit: cover;
    display: block;
}

.img-center {
    width: 100%;
    max-height: 380px;
    margin: 30px 0;
}

.grid-split {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 30px;
    align-items: center;
    margin: 30px 0;
}

.img-side {
    height: 320px;
}

/* Lists */
ul {
    padding-left: 20px;
    margin-bottom: 20px;
}

/* Code/Diagram Blocks */
pre {
    background-color: var(--pre-bg);
    color: var(--accent-glow);
    padding: 20px;
    border-radius: var(--radius);
    overflow-x: auto;
    font-family: 'Courier New', Courier, monospace;
    font-size: 0.88rem;
    line-height: 1.4;
    margin: 25px 0;
    border: 1px solid var(--border-color);
}

/* Data Tables */
.table-responsive {
    overflow-x: auto;
    margin: 25px 0;
}

table {
    width: 100%;
    border-collapse: collapse;
    background: var(--card-bg);
    border-radius: var(--radius);
    overflow: hidden;
    border: 1px solid var(--border-color);
}

th, td {
    padding: 14px 18px;
    text-align: left;
    border-bottom: 1px solid var(--border-color);
}

th {
    background-color: var(--primary-light);
    color: var(--text-main);
    font-weight: 600;
    font-size: 0.95rem;
}

td {
    font-size: 0.95rem;
    color: var(--text-main);
}

tr:last-child td {
    border-bottom: none;
}

/* Contact Section */
.contact-container {
    background: var(--contact-bg);
    padding: 30px;
    border-radius: var(--radius);
    border-left: 5px solid var(--accent);
    margin-top: 30px;
}

.contact-container h3 {
    color: var(--primary);
    margin-bottom: 15px;
    font-size: 1.2rem;
}

.contact-links {
    display: flex;
    flex-wrap: wrap;
    gap: 20px;
}

.contact-item {
    background: var(--card-bg);
    padding: 12px 20px;
    border-radius: 8px;
    font-size: 0.95rem;
    box-shadow: 0 2px 4px rgba(0,0,0,0.04);
    border: 1px solid var(--border-color);
}

.contact-item strong {
    color: var(--primary);
}

.contact-item a {
    color: var(--accent);
    text-decoration: none;
}

.contact-item a:hover {
    text-decoration: underline;
}

/* Related Section & Cards */
.related-section { 
    margin-top: 50px; 
    padding-top: 30px; 
    border-top: 2px solid var(--border-color); 
}

.related-grid { 
    display: grid; 
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr)); 
    gap: 20px; 
    margin-top: 20px; 
}

.blog-card { 
    background: var(--card-bg); 
    border: 1px solid var(--border-color); 
    border-radius: 12px; 
    overflow: hidden; 
    box-shadow: 0 4px 6px rgba(0,0,0,0.03); 
}

.blog-card-media { 
    height: 160px; 
    background: var(--img-slot-bg); 
    overflow: hidden; 
}

.blog-card-media img { 
    width: 100%; 
    height: 100%; 
    object-fit: cover; 
}

.blog-card-body { 
    padding: 20px; 
}

.blog-topic-badge { 
    display: inline-block; 
    background: var(--img-slot-bg); 
    color: var(--accent); 
    padding: 4px 10px; 
    border-radius: 6px; 
    font-size: 0.75rem; 
    font-weight: 700; 
    text-transform: uppercase; 
    margin-bottom: 10px; 
}

.blog-card-title { 
    font-size: 1.1rem; 
    color: var(--primary); 
    margin-bottom: 10px; 
    line-height: 1.3; 
}

.blog-card-summary { 
    font-size: 0.88rem; 
    color: var(--text-muted); 
    margin-bottom: 15px; 
}

.btn-read-more { 
    color: var(--accent) !important; /* Uses #0288d1 in light mode and #38bdf8 in dark mode */
    font-weight: 600; 
    text-decoration: none !important; /* Removes underline by default */
    font-size: 0.9rem; 
    display: inline-flex; 
    align-items: center; 
    gap: 6px; 
    transition: color 0.2s ease, text-decoration 0.2s ease;
}

.btn-read-more:hover {
    text-decoration: underline !important; /* Only applies underline on hover */
    color: var(--accent-glow); /* Brightens text slightly on hover */
}

/* Responsive Layout Adjustments */
@media (max-width: 768px) {
    body { padding: 20px 12px; }
    .page-card { padding: 25px; }
    .grid-split { grid-template-columns: 1fr; }
    .grid-split.reverse { display: flex; flex-direction: column-reverse; }
    h1 { font-size: 1.8rem; }
} 

/* Scrollbar Customization */
* {
    scrollbar-width: thin;
    scrollbar-color: var(--accent) rgba(0, 0, 0, 0.05);
}

::-webkit-scrollbar {
    width: 7px !important;
    height: 7px !important;
}

::-webkit-scrollbar-track {
    background: rgba(0, 0, 0, 0.05) !important;
    border-radius: 10px !important;
}

::-webkit-scrollbar-thumb {
    background: var(--accent) !important;
    border-radius: 10px !important;
}

::-webkit-scrollbar-thumb:hover {
    background: #0288d1 !important;
}